The present invention relates to a method and apparatus for controlling a semiconductor memory device, and more particularly, to a method and apparatus for controlling a data erasing operation of a non-volatile semiconductor memory device, such as a flash memory.
As shown in FIG. 1, a conventional flash memory has a plurality of data blocks 2a, 2b, each of which comprises eight sectors, labeled 1a-1h in the block 2a, for storing a data set. In such flash memory, data sets stored in each of the sectors 1a-1h are erased on a per-data-block basis. More specifically, for example, in a case where data sets are written in sectors 1a, 1c, 1d, and 1g within the data block 2a, if there is a desire to erase solely the data set written in sector 1c, there is no alternative but to collectively delete all of the data sets held within the data block 2a.
For this reason, if there is a desire to maintain the data sets written in sectors 1a, 1d, and 1g, all of the data sets stored in the data block 2a must be collectively erased after the data sets stored in sectors 1a, 1d, and 1g have been saved in another data block 2b.
Erasing a data set on a sector-by-sector basis is difficult for the conventional flash memory. For instance, if there is a desire to erase a single data set stored in a desired sector, there arises the need for complicated data transfer processing.
An object of the present invention is to provide a control method and apparatus which erases data in a sector-by-sector manner.